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Police forces across the United Kingdom effectively campaigned to deploy a face scanning system acknowledged as biased against women, young people, and members of ethnic minority groups, following complaints that a more accurate version generated a reduced number of investigative leads.

How the System Works

British police utilize the police national database (PND) to carry out retrospective facial recognition searches. This procedure entails matching a reference photograph of a person of interest against a repository of more than 19 million mugshots to identify possible hits.

Admitted Bias

The UK interior ministry admitted last week that the technology was flawed. This admission followed a review by the National Physical Laboratory (NPL) determined it misidentified people of Black and Asian heritage and women at significantly higher rates than Caucasian males. The ministry stated it “took steps on the findings”.

“This raises the issue of whether this technology only becomes effective if users tolerate discrimination in ethnicity and gender. Convenience is a poor argument for overriding fundamental rights.”

Known Issue

Official papers show that this discriminatory flaw has been recognized for more than a year. Furthermore, law enforcement lobbied to reverse an initial decision that was intended to address the problem.

Police bosses were notified of the algorithmic discrimination in September 2024. The government-ordered laboratory study found the system was more likely to produce incorrect matches for photos of females, individuals of Black ethnicity, and those aged 40 and under.

A Policy U-Turn

In reaction, the National Police Chiefs’ Council (NPCC) mandated that the accuracy setting required for possible hits be raised to a point where the bias was significantly reduced.

However, this decision was overturned the next month following complaints from police that the modified technology was generating fewer “useful lines of inquiry”. NPCC documents indicate the stricter setting cut the proportion of searches resulting in potential matches from 56% to a mere under 15%.

Severe Disparities

Although the authorities declined to specify what threshold is currently used, the recent NPL study discovered the system could produce incorrect matches for women of Black heritage nearly a hundred times more often than for Caucasian women at specific configurations.

The Home Office commented on these findings: “The testing identified that in a specific scenarios the algorithm is has a greater tendency to wrongly flag some population segments in its match reports.”

Operational Effectiveness vs. Bias

Outlining the impact of the temporary raise to the system's accuracy setting, the police records state: “This adjustment significantly reduces the impact of discrimination across legally safeguarded attributes of ethnicity, age and gender but had a substantially detrimental effect on police efficiency”. The papers further note that forces complained that “a once effective tactic returned outcomes of questionable value”.

Wider Implementation Proposals

Meanwhile, the government has launched a two-and-a-half-month public review on its proposals to widen the use of biometric scanning systems. The minister for police Sarah Jones has labeled the technology as the “most significant advance since genetic fingerprinting”.

Criticism from Advisors and Monitors

Abimbola Johnson, chair of the advisory panel for the national policing equality strategy, commented: “We observed scant discussion through equality strategy sessions of the technology deployment despite obvious cross-over with the plan’s concerns.

“These revelations demonstrate yet again that the pledges to combat discrimination the police has made through the equality initiative are failing to be integrated into wider practice. Independent assessments have warned that innovative tools are being rolled out in a landscape where racial disparities, inadequate oversight and poor data collection already persist.

“All deployment of this technology must meet strict national standards, be subject to external review, and prove it reduces rather than exacerbates racial disparity.”

Official Statement

A government representative said: “The Home Office treat the findings of the study seriously and we have implemented changes. A updated software has been externally evaluated and acquired, which has no statistically significant bias. It will be trialled in the coming months and will be subject to evaluation.

“The foremost aim is ensuring public safety. This gamechanging technology will assist police to put criminals and rapists behind bars. There is human involvement in each stage of the procedure and no arrest or charge would be taken without specialist personnel carefully reviewing the results.”